基于甲氧基柱[5]芳烃的聚丙烯酸酯有机膜对对硝基苯衍生物的吸附行为

柱芳烃是一类有别于冠醚、杯芳烃、葫芦脲等的柱状大环分子,具有独特的富电子空腔和口腔的可修饰性。 它们可以包结多种有机污染物,对有机污染物的吸附和脱除具有广泛的应用前景。 本文通过核磁共振和紫外滴定的方法首先研究了对硝基苯衍生物与甲氧基柱5]芳烃(MeP5A)的包结行为,测定了包结常数。 在此基础上,将MeP5A物理混合到聚丙烯酸酯(PA)乳液中,首先制备了甲氧基柱5]芳烃/聚丙烯酸酯(MeP5A/PA)共混乳液,然后通过静电纺丝技术,得到了MeP5A/PA纳米纤维膜。 采用红外光谱、扫描电子显微镜对MeP5A/PA纳米纤维膜的结构和形貌进行了表征。 将MeP5A/PA纳米纤维膜用于4种对硝基苯衍生物的吸附实验。 结果表明,对硝基苯乙腈显示出与MeP5A最强的包结作用,其K_a=(6.0±0.3)×10² L/mol,PA膜中引入MeP5A,增大了吸附量,但并未改变纤维状形貌。 MeP5A/PA纳米纤维膜的最佳吸附平衡时间为2 h,且MeP5A/PA纳米纤维膜中MeP5A的含量越高,吸附量越大。 但当吸附溶液中MeP5A浓度达到4 mmol/L时(对应的膜中含有的MeP5A物质的量为1.4×10^-2 mmol),其吸附基本达到平衡,继续增加MeP5A物质的量,其吸附量变化不大。

Adsorption of p-Nitrobenzene Derivatives by Polyacrylate Organic Membranes Based on 1,4-Dimethoxy Pillar[5]arenes

Pillararenes are columnar macrocyclic molecules that are different from crown ethers, calixarenes, and cucurbiturils, and have unique electron-rich cavities and modifiable mouth cavities. They can contain a variety of organic pollutants, and have broad application prospects for the adsorption and removal of organic pollutants. In this paper, the complexation of p-nitrobenzene derivatives with 1,4-dimethoxy pillar5]arenes(MeP5A) was studied by nuclear magnetic resonance and ultraviolet titration, and the inclusion constant was determined. On this basis, MeP5A was physically mixed into polyacrylate(PA) emulsion to prepare the MeP5A/polyacrylate(MeP5A/PA) blending emulsion. Then, the blending emulsion was made into the MeP5A/PA nanofiber membrane by the electrospinning technology. The structure and morphology of the MeP5A/PA nanofiber membrane were characterized by infrared spectroscopy and scanning electron microscopy. The MeP5A/PA nanofiber membrane was used for adsorption of four kinds of p-nitrobenzene derivatives. The results reveal that p-nitrophenylacetonitrile holds the strongest complexation intensity with MeP5AK_a=(6.0±0.3)×10² L/mol]. The introduction of MeP5A into the PA nanofiber membrane increases the adsorption capacity but does not change the fibrous morphology. The optimum adsorption equilibrium time of MeP5A/PA nanofiber membranes is 2 h, and the higher the content of MeP5A in MeP5A/PA nanofiber membranes, the larger the adsorption capacity. When the concentration of MeP5A in the adsorbed solution reaches 4 mmol/L(the corresponding MeP5A mole in the membrane is 1.4×10^-2 mmol), the adsorption equilibrium is reached. Then the content of MeP5A continues to increase, and the adsorption capacity does not change much.